From ec310caf13b5505c268cfa526b7b28152a879d1e Mon Sep 17 00:00:00 2001 From: Brijesh Singh Date: Tue, 12 Nov 2019 13:58:34 -0600 Subject: [PATCH] crypto: ccp - add SEV command privilege separation Currently, there is no privilege separation of the SEV command; you can run them all or none of them. This is less than ideal because it means that a compromise of the code which launches VMs could make permanent change to the SEV certifcate chain which will affect others. These commands are required to attest the VM environment: - SEV_PDH_CERT_EXPORT - SEV_PLATFORM_STATUS - SEV_GET_{ID,ID2} These commands manage the SEV certificate chain: - SEV_PEK_CERR_IMPORT - SEV_FACTORY_RESET - SEV_PEK_GEN - SEV_PEK_CSR - SEV_PDH_GEN Lets add the CAP_SYS_ADMIN check for the group of the commands which alters the SEV certificate chain to provide some level of privilege separation. Cc: Herbert Xu Cc: Gary Hook Cc: Erdem Aktas Cc: Tom Lendacky Tested-by: David Rientjes Co-developed-by: David Rientjes Signed-off-by: David Rientjes Signed-off-by: Brijesh Singh Signed-off-by: Herbert Xu --- drivers/crypto/ccp/psp-dev.c | 29 ++++++++++++++++++++++------- drivers/crypto/ccp/psp-dev.h | 1 + 2 files changed, 23 insertions(+), 7 deletions(-) diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c index c4da8d1..5ff842c 100644 --- a/drivers/crypto/ccp/psp-dev.c +++ b/drivers/crypto/ccp/psp-dev.c @@ -294,6 +294,9 @@ static int sev_ioctl_do_reset(struct sev_issue_cmd *argp) { int state, rc; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + /* * The SEV spec requires that FACTORY_RESET must be issued in * UNINIT state. Before we go further lets check if any guest is @@ -338,6 +341,9 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp) { int rc; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (psp_master->sev_state == SEV_STATE_UNINIT) { rc = __sev_platform_init_locked(&argp->error); if (rc) @@ -354,6 +360,9 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp) void *blob = NULL; int ret; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (copy_from_user(&input, (void __user *)argp->data, sizeof(input))) return -EFAULT; @@ -540,6 +549,9 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp) void *pek_blob, *oca_blob; int ret; + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + if (copy_from_user(&input, (void __user *)argp->data, sizeof(input))) return -EFAULT; @@ -695,6 +707,16 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp) struct sev_data_pdh_cert_export *data; int ret; + /* If platform is not in INIT state then transition it to INIT. */ + if (psp_master->sev_state != SEV_STATE_INIT) { + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + ret = __sev_platform_init_locked(&argp->error); + if (ret) + return ret; + } + if (copy_from_user(&input, (void __user *)argp->data, sizeof(input))) return -EFAULT; @@ -741,13 +763,6 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp) data->cert_chain_len = input.cert_chain_len; cmd: - /* If platform is not in INIT state then transition it to INIT. */ - if (psp_master->sev_state != SEV_STATE_INIT) { - ret = __sev_platform_init_locked(&argp->error); - if (ret) - goto e_free_cert; - } - ret = __sev_do_cmd_locked(SEV_CMD_PDH_CERT_EXPORT, data, &argp->error); /* If we query the length, FW responded with expected data. */ diff --git a/drivers/crypto/ccp/psp-dev.h b/drivers/crypto/ccp/psp-dev.h index 82a084f..dd516b3 100644 --- a/drivers/crypto/ccp/psp-dev.h +++ b/drivers/crypto/ccp/psp-dev.h @@ -23,6 +23,7 @@ #include #include #include +#include #include "sp-dev.h" -- 2.7.4